<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <com.example.homework.PostView
            android:id="@+id/firstPost"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

        <com.example.homework.PostView
            android:id="@+id/secondPost"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

        <com.example.homework.PostView
            android:id="@+id/thirdPost"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    </LinearLayout>
</ScrollView>